I would suggest the same applies to builders. If a person wants to go cruising but has limited time & money, their best course of action by far is to buy an existing boat and prep it to suit.
No-one can build a boat remotely as cheaply as something similar can be bought used.
I speak from experience.
You are absolutely right, plastic boats are much cheaper, if you are content to have nothing but apiece of plastic between you and any dangerous floating debris out there, nothing but a piece of plastic between you and sudden death for you and your crew( bad seamanship) Or if you are content with the leaky dampness of living under a plastic deck , and having to rebed your deck gear and chase down leaks frequently. Most of my clients have done that, and consider it worth the time, money and effort to solve the problem permanently, with a steel boat. Before Silas Crosby, Steve had a Spencer 35, which he sailed to New Zealand and back to BC. He flew home and began Silas Crosby when he reached Hawaii in his plastic boat.
Any steel boat designer can do a lot to reduce the time and money required , for anyone who doesn't want to risk his life, and that of his crew, in fragile plastic , and wishes to enjoy the hugely enhanced comfort and safety of a steel boat, by simply using my methods. I don't exactly keep them a dark trade secret. There is very little choice around here in used boats, for anyone wanting a good, affordable steel boat. Mine are usually the only show in town